Key to the vaccine's success is a liposome the developers created called cobalt-porphyrin-phospholipid, or CoPoP. They are tiny spherical sacs, which are small enough to be considered nanoparticles, and they form the backbone of the vaccine platform.
Described in a study published on May 24 by the Proceedings of the National Academy of Science, the experimental vaccine has reportedly proven effective in preclinical studies.
“The results are very encouraging,” says the study's senior author, Jonathan Lovell, PhD, associate professor of biomedical engineering at the University at Buffalo, New York.
Liposomes spontaneously convert virus proteins that prompt immune responses into a more potent nanoparticle format, said the team behind the development of the vaccine.
"This conversion is advantageous because the dissolved proteins attach to the surface of the liposomes, where the proteins enhance the immune system's response to disease," says senior author, Matthew Miller, PhD, associate professor of biochemistry and biomedical sciences at McMaster University, a public research university in Ontario, Canada.
In summary, the experimental flu vaccine, according to the research team behind the study, has the potential to:
- Improve the effectiveness of seasonal flu vaccines
- Take less time to produce large quantities because, unlike most seasonal flu vaccines, it is not created in embryonated chicken eggs
- Use smaller doses, thereby increasing vaccine supplies, which can be critical given the unpredictable nature of influenza.
In the study, the researchers introduced a group of proteins – hemagglutinin - to the CoPop liposomes. They saw that one particular hemagglutinin - trimeric H3 HA - triggered a strong immune response in mice.
"The nanoparticles carry the trimeric H3 HA to the body's immune cells, and they provoke those immune cells to respond more vigorously to the flu," said lead author Zachary Sia, a PhD candidate in Lovell's lab.
In experiments involving flu virus strain H3N2, blood serum from vaccinated mice was injected into non-vaccinated mice. The injection provided protection against H3N2. In experiments with ferrets involving a more modern H3N2 strain, the vaccine reduced the amount of virus in the animals' upper respiratory system, said the research team.
Even with doses as low as two nanograms, the vaccine provided a similar level of protection as vaccines with doses typically measured in micrograms, or roughly 1,000 times more, they reported.
"The dose-sparing effect is important because it means we could create many more doses using less materials," said senior co-author Bruce Davidson, PhD, research associate professor of anesthesiology in the Jacobs School of Medicine and Biomedical Sciences, the University of Buffalo.
CoPoP likely will provide greater immune protection with less hemagglutinin than current vaccines, he stressed.
While not part of this study, the same platform is being utilized in clinical trials in South Korea as a COVID-19 vaccine candidate. This is a partnership between UB spinoff company POP Biotechnologies, co-founded by Lovell, and South Korean biotech company EuBiologics. POP Biotechnologies is also working with Scripps Research to study the platform in a possible HIV vaccine.
Lovell and another co-author of the study, Wei-Chiao Huang, hold interest in POP Biotechnologies.
Funding for the research
Funding to support the study came from the US National Institutes of Health, from a Canadian Institutes of Health Research (CIHR) New Investigator Award from the Government of Ontario, a Physicians Services Inc. Research Trainee Fellowship, and a CIHR Canada Graduate Scholarship.
Additional support came from the Veterans Affairs Western New York Healthcare System, the Facility for Electron Microscopy Research at McGill University, and the Canadian Foundation for Innovation and the Government of Quebec.